An electrochemical cell is formed by ion motion in a solution between an anode and a cathode, or electron movement in external metal wires between the anode and the cathode. For example, in an electroplating process of a semiconductor manufacturing process, ions in a solution are used to deposit a thin-film metal layer.
In an electrochemical cell, an external-linking external electrode is usually adopted to connect to a plurality of internal electrodes on a chip. The distance between the external electrode and the internal electrode is longer due to the external-linking external electrode. If the distance between the external electrode and the internal electrode is shortened, a potential drop (IR drop) caused by a solution between the electrodes can be reduced and the electrode field between the electrodes also can be improved to enhance ion motion resulting in electric current increasing.
In semiconductor manufacturing processes, if a cavity is formed by a bonding procedure, some problems such as poor bonding and alignment error may occur during the formation processes of the cavity. Especially, when the size of the electrochemical cell is reduced, these problems such as poor bonding and alignment error are more likely to be serious.